Denture



Patented Nov. 21, 1939 UNITED IKSTATES PATENT OFFICE DENTURE Charles H.Prange, Lyndhurst, N. J., assignor to Animal Laboratories,

a corporation of New York N Drawing. Applica Serial No. 198,491

R Claims.

. 725,651, filed' May 14, 1934, which has matured into Patent No.2,135,600, patented November 8, 1938.

As set forth in my above identified copending application, I have foundthat alloys of higher tungsten and molybdenum content than specified inmy above identified prior patent are practicable without impairing thecharacteristics and advantageous properties of the dentures and withadditional advantageous results.

The copending application, of which the present application is acontinuatiomin-part, is directed to dentures with a higher tungstencontent than set forth in my prior patent.

The present application is directed to dentures with a higher molybdenumcontent in my prior patent.

'I have found that exceptional toughness and the desired resilience ofthe denture or denture part may be obtained by keeping the carboncontent low and increasing the molybdenum content. In other words,according to the present invention, a denture or denture part formed ofan alloy having cobalt as the principal constituent andcontainingchromium approximately ten to forty per cent and with a'low carboncontent has exceptional toughness, and that the desired resilience canbe secured in this low carbon alloy by increasing the molybdenumcontent.

I have found further that dentures and denture parts made of alloys ofthe character more fully set forth in my prior patent but with anincreased molybdenum content, and either with or without a smallpercentage of carbon, not only have exceptional toughness and betterresilience, but also the additional advantageous property of improvedresistance to acid.

The matter of "the reduced carbon content which is made possible withoutlessened resilience by the increased molybdenum content is an importantaspect of the present invention.

For a full understanding of the dentures of my prior patent and thecharacteristics and advantageous properties of the dentures of thatpatent, which characteristics and advantageous properties are preservedin the alloy dentures of the present application, reference is made hereto my prior patent, and the disclosure of that than set forth Inc.,' NewYork, N. Y.,

tion -March- 28, 1938,

patent is hereby incorporated in this application as if forming a partthereof.

I have found that the characteristics and advantageous properties of thealloy dentures of my prior patent may be retained and further improvedresults secured by increasing the molybdenum content. It is not possibleto carry the molybdenum content quite as high as the tungsten contentmay be carried according to my copending application Serial No. 725,651,filed May 14, 1934, but a molybdenum content up to asvhigh as abouttwenty per cent is contemplated within the scope of my presentinvention. According to my present invention the denture or denture partcomprises an alloy having cobalt as the, principal or essentialconstituent, and conthins chromium from approximately-ten per cent toapproximately forty per cent and molybdenum up to approximately twentyper cent. With twelve per cent molybdenum the alloy is very tough, butwith twenty per cent molybdenum, in combination with thirty per centchromium, it is decidedly brittle. It is possible tointroduce carbon tothe extent of about .6 per cent into an alloy containing twelve per centmolybdenum without obtaining a brittle alloy.

To summarize, it is possible to make desirable dentures of an alloyhaving cobalt as the principal constituent and containing chromiumapproximately ten to approximately forty per cent and with a molybdenumcontent increased beyond that disclosed in my )prior patent, either withor without a small percentage of carbon.

.The increased molybdenum content results in better resilience and hasthe further advantage of bringing about improved resistance to acid,such as hydrochloric acid.

per cent brings about'brittleness which tends toward unusable alloys. Asan alternative for The addition of 1 molybdenum in 'excess ofapproximately twenty avoiding brittleness, the chromium content may bereduced.

' In the more specific aspects of the invention the denture or denturepart comprises an alloy having cobalt as the principal constituent andcontains chromium approximately ten to thirty per cent and molybdenum upto approximately twenty per cent and carbon from about .6 per cent downto substantially .0 per cent, the molybdenum con-'- tent being increasedin inverse proportion to the carbon content so as to provide thecharacteristics of high resilience combined with toughness and highresistance to acid.

The substantially carbonless alloys-of this type have exhibited aresilience superior to thedenture alloyof my prior patent, combined witha higher degree of toughness, and have at the same time the advantageousproperties of the denture alloy of my prior patent. These alloys are ofpractical value, not only for casting purposes in accordance with myprior patent, but for the production of wrought wires to be used indentistry for making clasps and the like. The carbonless orsubstantially carbonless alloys have an advantage in that it is easierto maintain uniform physical characteristics.. these alloys being verysensitive to-the small variations in the carbon content which, inpractical work, are'very difficult to control. Some carbon is allowable,particularly in the lower molybdenum ranges approaching the molybdenumcontent of the denture alloy of my prior patent without causingbrittleness. I

In casting a denture of the alloy specified herein, it isv essential toemploy a mold of high refractoriness. For this purpose, the mold andcasting method of my prior patent, or any other equivalent or suitablemold and casting process, may be employed. The mold and casting processmore fully described in my prior patent constitute one suitable mold andcasting process for casting dentures of the alloys of the presentapplication. The mold and process of my prior patent are referred toherein, not for limiting the present invention to formation of thedenture with this mold and process, but for adequately acquainting thoseskilled in the art with one suitable mold and process for casting thedentures of my present invention.

The casting investment material and process disclosed in my prior PatentNo. 2,081,558, patented May 25, 1937, are also highly suitable andadvantageous in the casting of dentures of the alloys of my presentinvention, and reference is hereby incorporated herein for the furtherdetails of the casting investment material and process of the last abovementioned patents as a casting investment material and process suitablefor casting dentures of the alloys of my present invention.

I claim:

1. As a new article of manufacture, a denture comprising an alloy havingcobalt as the principal constituent and containingchromium fromapproximately ten per cent to approximately forty per cent andmolybdenum over five per cent and not exceeding approximately twenty percent, said denture having the characteristic of slight shrinkage insolidifying.

2. As a new article of manufacture, a prosthetic article comprising analloy having cobalt as the principal constituent and containing chromiumapproximately ten per cent to approximately forty per cent andmolybdenum over five-per cent and not exceeding approximately twenty percent, said alloy prosthetic article having the characteristic of slightshrinkage in solidifying.

3. As a new article of manufacture, a denture comprising an alloy havingcobalt as the principal constituent and containing molybdenumapproximately twelve per cent and chromium approximately thirty percent, said alloy denture having the characteristic of slight shrinkagein solidify- 4. As a new article of manufacture, a denture comprising analloy having cobalt as the principal constituent-and containingmolybdenum approximately twelve per cent, chromium approximately thirtyper cent, and carbon up to approximately .6 per cent, said alloy denturehaving the characteristic of slight shrinkage in solidifying.

5. As a new article of manufacture, a denture comprising an alloy havingcobalt as the principal constituent and containing chromiumapproximately ten to thirty per cent and molybdenum up to approximatelytwenty per cent and carbon from .6 per cent down to substantially .0 percent, the molybdenum being increased in inverse proportion to the carboncontent so as to provide the characteristics of high resilience combinedwith toughness and high resistance to acid, said alloy denture havingthecharacteristic of slight shrinkage in solidifying.

CHARLES H. PRANGE.

